[WIP]test: setup itk resubscribe tests

[kdziedzic70]

Description

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Fixes #<issue_number_goes_here> 🦕

[gemini-code-assist]

Code Review

This pull request introduces 'resubscribe' and 'hold task' behaviors to the ITK agent, adds helper functions for event and task management, and improves resource handling via an asynchronous context manager for the HTTP client. It also implements signal handling for graceful shutdowns, updates agent capabilities, and expands the test suite. Feedback was provided to correct Protobuf field presence checks and enum comparisons, remove a deprecated parameter, and restore configurable logging for the uvicorn server.

[gemini-code-assist]

The logic to extract task_obj from the event is potentially incorrect. For a protobuf message like StreamResponse, hasattr(event, 'task') will always be True, but this doesn't mean the task field is actually set in the message. Accessing event.task when the field is not set will give you a default Task instance, which is likely not what you want. The correct way to check for presence is event.HasField('task').

The elif condition is currently unreachable because the if condition will always be met for a StreamResponse object. I suggest simplifying this block to correctly check for the task field.

Suggested change

	if hasattr(event, 'task'):
	task_obj = event.task
	elif hasattr(event, 'HasField') and event.HasField('task'):
	task_obj = event.task
	if event.HasField('task'):
	task_obj = event.task

[gemini-code-assist]

Comparing the role enum field with strings like 'ROLE_AGENT' or 'agent' is not reliable and is likely incorrect. Protobuf enums in Python are integers, so this comparison will likely always evaluate to false. You should compare msg.role with the actual enum member.

To do this, you'll need to import Role from a2a.types.a2a_pb2 at the top of the file.

Suggested change

	if msg.role == 'ROLE_AGENT' or msg.role == 'agent':
	if msg.role == Role.ROLE_AGENT:

[gemini-code-assist]

The context parameter of BasePushNotificationSender is deprecated and will be removed in a future version. The constructor logs a warning when it is used. You can safely remove it from this call.

    push_sender = BasePushNotificationSender(
        httpx_client=httpx_client,
        config_store=push_config_store,
    )

[gemini-code-assist]

The log_level for uvicorn is now hardcoded to 'info'. This removes the ability to configure it using the ITK_LOG_LEVEL environment variable. It's better to restore the previous behavior to allow for flexible log level configuration during testing.

Suggested change

	app, host='127.0.0.1', port=http_port, log_level='info'
	app, host='127.0.0.1', port=http_port, log_level=log_level_str.lower()